τ²-bench implements a simulation framework for evaluating customer service agents across various domains.
Note: This module is part of the consolidated
agent-framework-labpackage. Install the package with thetau2extra to use this module.
The framework orchestrates conversations between two AI agents:
- Customer Service Agent: Follows domain-specific policies and has access to tools (e.g., booking systems, databases)
- User Simulator: Simulates realistic customer behavior with specific goals and scenarios
Each evaluation runs a multi-turn conversation where the user simulator presents a customer service scenario, and the agent must resolve it following the domain policy while using available tools appropriately. The results are evaluated using τ²'s comprehensive evaluation system.
| Domain | Status | Description |
|---|---|---|
| airline | ✅ Supported | Customer service for airline booking, changes, and support |
| retail | 🚧 In Development | E-commerce customer support scenarios |
| telecom | 🚧 In Development | Telecommunications service support |
Note: Currently only the airline domain is fully supported.
Install the agent-framework-lab package with TAU2 dependencies:
pip install "agent-framework-lab[tau2]"Important: You must also install the tau2-bench package from source:
pip install "tau2 @ git+https://github.com/sierra-research/tau2-bench@5ba9e3e56db57c5e4114bf7f901291f09b2c5619"Download data from Tau2-Bench:
git clone https://github.com/sierra-research/tau2-bench.git
mv tau2-bench/data/ .
rm -rf tau2-benchExport the data directory to TAU2_DATA_DIR environment variable:
export TAU2_DATA_DIR="data"import asyncio
from agent_framework.openai import OpenAIChatClient
from agent_framework.lab.tau2 import TaskRunner
from tau2.domains.airline.environment import get_tasks
async def run_single_task():
# Initialize the task runner
runner = TaskRunner(max_steps=50)
# Set up your LLM clients
assistant_client = OpenAIChatClient(
base_url="https://api.openai.com/v1",
api_key="your-api-key",
model_id="gpt-4o"
)
user_client = OpenAIChatClient(
base_url="https://api.openai.com/v1",
api_key="your-api-key",
model_id="gpt-4o-mini"
)
# Get a task and run it
tasks = get_tasks()
task = tasks[0] # Run the first task
conversation = await runner.run(task, assistant_client, user_client)
reward = runner.evaluate(task, conversation, runner.termination_reason)
print(f"Task completed with reward: {reward}")
# Run the example
asyncio.run(run_single_task())Use the provided script to run the complete benchmark:
# Run with default models (gpt-4.1 for both agent and user)
python samples/run_benchmark.py
# Use custom models
python samples/run_benchmark.py --assistant gpt-4o --user gpt-4o-mini
# Debug a specific task
python samples/run_benchmark.py --debug-task-id task_001 --assistant gpt-4o
# Limit conversation length
python samples/run_benchmark.py --max-steps 20The following results are reproduced from our implementation of τ²-bench with samples/run_benchmark.py. It shows the average success rate over the dataset of 50 tasks.
| Agent Model | User Model | Success Rate |
|---|---|---|
| gpt-5 | gpt-4.1 | 62.0% |
| gpt-5-mini | gpt-4.1 | 52.0% |
| gpt-4.1 | gpt-4.1 | 60.0% |
| gpt-4.1-mini | gpt-4.1 | 50.0% |
| gpt-4.1 | gpt-4o-mini | 42.0% |
| gpt-4o | gpt-4.1 | 42.0% |
| gpt-4o-mini | gpt-4.1 | 26.0% |
Set required environment variables:
export OPENAI_BASE_URL="https://api.openai.com/v1"
export OPENAI_API_KEY="your-api-key"
# Optional: for custom endpoints
export OPENAI_BASE_URL="https://your-custom-endpoint.com/v1"from agent_framework.lab.tau2 import TaskRunner
from agent_framework import ChatAgent
class CustomTaskRunner(TaskRunner):
def assistant_agent(self, assistant_chat_client):
# Override to customize the assistant agent
return ChatAgent(
chat_client=assistant_chat_client,
instructions="Your custom system prompt here",
# Add custom tools, temperature, etc.
)
def user_simulator(self, user_chat_client, task):
# Override to customize the user simulator
return ChatAgent(
chat_client=user_chat_client,
instructions="Custom user simulator prompt",
)from agent_framework import WorkflowBuilder, AgentExecutor
from agent_framework.lab.tau2 import TaskRunner
class WorkflowTaskRunner(TaskRunner):
def build_conversation_workflow(self, assistant_agent, user_simulator_agent):
# Build a custom workflow
builder = WorkflowBuilder()
# Create agent executors
assistant_executor = AgentExecutor(assistant_agent, id="assistant_agent")
user_executor = AgentExecutor(user_simulator_agent, id="user_simulator")
# Add workflow edges and conditions
builder.set_start_executor(assistant_executor)
builder.add_edge(assistant_executor, user_executor)
builder.add_edge(user_executor, assistant_executor, condition=self.should_not_stop)
return builder.build()from agent_framework.lab.tau2 import patch_env_set_state, unpatch_env_set_state
# Enable compatibility patches for τ²-bench integration
patch_env_set_state()
# Disable patches when done
unpatch_env_set_state()This package is part of the Microsoft Agent Framework Lab. Please see the main repository for contribution guidelines.
This project is licensed under the MIT License - see the LICENSE file for details.